Zen, as it applies to kenjutsu or anything else is not a simple thing to explain, and it is also well known that if one is to understand Zen, then that understanding is to come from your own experiences and insigts, not from outside teachings, either from a teacher or from a book. The difference of true understanding [satori] and thinking you understand is quite different. There are many Budo which are a way to practice Zen. The Samurai recognised this and as such, arts such as Cha-no-yu [tea ceremony], Shodo [Calligraphy], Ikebana [flower arranging] as well as Za-Zen [sitting meditation] were all popular in addition to sword training. There are many stories which illustrate the parallels of different Budo through the commonality of Zen. If one has reached a true understanding of Zen, then this understanding should apply to all the Zen arts. There are many ways to do Zen, but having an object to focus your efforts and relax your mind makes it a little easier. In Iaido the object is your sword, in Shodo it is the fude [writing brush], in Cha-no-yu it is the tea. Za-Zen is probably the hardest because all you have to focus your efforts on is yourself. All Budo are just different ways to walk the road towards attaining Satori, and as such any martial art that is concerned with attaining satori as oppsed to killing people, can be called Budo.
The often frustrating and confusing thing about Zen is its simplicity, while at the same time, its complexity. The central idea is that you need to walk around the long way to realize that there was a shortcut there all the time. This means that you can only realize the simplicity of things after years of training, so in essence, the shortcut you realize, isn’t a shortcut at all and this realization is also very important.
Mugai-ryu and Zen have a very close relationship. Mugai ryu's founder, Tsuji Gettan Sukemochi trained as a Zen So [monk] in the late 1600’s in Japan. It was a requirement that any student of Tsuji Gettan’s must first enter into training at a Zen temple before being accepted into the Mugai-ryu dojo. As such, Mugai-ryu has a very strong Zen influence which can be seen in the compactness and lack of surplus movement in the kata, orei [“Namu-Amida-Butsu” or similar] for the dead enemy’s soul and fusatsuto [non killing sword] of the Naiden kata.
All the kata in Mugai-ryu [and generally in Iaido] are response to an attack. True to the principals of Zen, the true Iaido-ka is pacifist. One does not provoke the fight nor wish to show off and make a showy display of one’s skill with the sword. The Zen Kenshi doesn’t kill the enemy, his enemy brings about his own death by his aggression. The enemy, being rather less enlightened seeks out a fight and has strong aggression [if he was enlightened, he wouldn't be aggressive], if you have a state of Munen Muso [無念無想] then your still, settled state of mind reflects that aggression and you react almost subconsciously, but in the correct way. This is shown particularly in Mugai-ryu by the style of all the kata. They aren’t showy or flashy, they don’t utilize tricks or deception, all are honestly straight forward and decisive. Also during the kata there are ample chances for the enemy to back down, you only kill him if he persists in trying to kill you. In the Zen sense, a Zen kenshi can’t be blamed for killing an oncoming attacker any more than the rocks at the bottom of a cliff can be blamed for killing the suicide jumper.
One of the more important points in Zen is ‘Mu’ [ 無] Mu is a mind and state of emptyness if you like. ‘Mu’ means no, un~, nothing, etc. [it’s the mu of Mugai-ryu]
Mushin [ 無心]
Mushin is being detached from your fear, surprise, doubt and preconception. You must see things as they really are, and see them instantly. Fear, surprise, doubt and preconception affect the way we see things, and change the reality. Ch’ung-Hsin said, “if you want to see, see right at once. When you begin to think, you miss the point”
It’s like the mind of a child, but with the benefit of experience to make the right decision.
Zen teaches us to be decisive and not to dither or have regrets. If you feel a choice is difficult it’s because you have the luxury of having 2 good things to choose from. If one of the things were so bad, then you would naturally not even consider it, so then it would be an easy choice. So if you feel that the choice is difficult, just choose quickly and have no regrets. This is also Mushin.
Mujushin [ 無住心]
Mujushin is non-abiding or non-attachment of your mindset. This means that your mind doesn’t rest with any one particular thought, but moves freely and unencumbered to be of the most use and flexibility to what is most important at the time. Takuan Soho said that wherever you put your mind, you will be taken there. If you concentrate on you feet, they will be your downfall, if you concentrate on your sword, then it will be your downfall. You need to let your mind be free to go where it is needed, let it work for you rather than overcontrol it so that it cant work to its best ability. This is of course different to letting your mind wander and think of all kinds of irrelevant things. This is called Zatsunen [雑念] and is even more of a hinderence. If you have trained enough, you can trust in your mind to do the right thing without your conscious input. Having Mushin and Mujushin means that your actions are automatic, fast and perfect.
Muga [ 無我]
Muga means no ego. If you worry about how you look, or if you’ll live or die, etc, then you’ll never reach the harmony and perfectness of Zen. Even if you win against your enemy, it wont be a perfect victory, but just chance. A famous Samurai [possibly Takeda Shingen or Uesugi Kenshin] once said to his troops before a battle; “Those who wish only to survive the battle will surely die, whereas those who go into battle with no thought of surviving it will come home alive” Note though that having no thought of surviving the battle is quite different to going into the battle seeking death.
Samurai were attracted to Zen long before it became mainstream in Japan. The Hojo family of Kamakura encouraged the introduction and development of Zen into Japan. For Samurai, the constant training of Mushin, Mujushin and Muga was of the same importance as training with the sword. A Samurai well trained in Zen means that courage is always with him, not something that needs to be summoned up when needed. When you think about what courage is, its certainly lack of fear, lack of self concern, lack of doubt, etc. Which is certainly Mushin and Muga.
Understanding Zen ties all the parts of Iaido together. Keep in mind the principle of Zen as you train and you will find that Iaido permeates your whole life. And that you don’t need a sword to train in Iaido. [無刀] This is certainly the highest ideal of iaido. Your state of being is so highly developed and your soul so polished from the pursuit of Iaido that even without a sword you will have the upper hand. If there is a fight, it will be because you choose to let the fight progress and whatever you have in your hands will become the weapon you will win with, even if your hands are empty. Equally in such a state of satori you will be able to choose not to fight if that is a more suitable path, but ultimately you are in control of whatever situation arises.
Zen is about being in a completely calm and relaxed state of mind so you can react instinctively. Years of training allows your instinctive reaction to be the most correct reaction. This is sometimes the point that most people miss. Zen is very simple, but you need to take the time before you arrive at that state. There is no shortcut to understanding and as experience is the base of your understanding, many years and many hours of perserverance is necessary before you can even start to see yourself make progress.